This invention is related to an improvement on the building exterior curtain wall mullion anchoring systems with an anchoring device secured to a cured concrete floor slab as described in U.S. Pat. No. 9,683,367 and U.S. Patent Application Publication No. 2017/0241133, which are incorporated by reference herein.
It is well known in the industry that a curtain wall mullion anchoring system must provide the capability of three-way construction tolerance adjustments due to imperfections in the position of the concrete floor slab edge and imprecision in the placement of mullion anchoring devices embedded in the floor slab when the concrete is poured. The first way is in the direction parallel to the length direction of the mullion and is commonly known as the up-and-down direction. The second way is in the direction perpendicular to the curtain wall surface and is commonly known as the in-and-out direction. The third way is in a direction parallel to the curtain wall surface and perpendicular to the length direction of the mullion and is commonly known as the left-and-right direction.
For a floor slab anchoring system, mullion erection can only start after the concrete floor slab has been cured. The first step of the mullion erection is to mark a reference line on the floor slab. The reference line is parallel to the curtain wall surface, at a known, fixed distance from the back surface of the mullion in its erected position. The reference line is used for in-and-out adjustment of the mullion anchoring system. The lateral (left/right) position of the mullion is also marked on the reference line. The next step is to bring a mullion (stick or airloop system) or a half mullion (integral part of a unitized unit) to the approximate location of the marked mullion line, followed by performance of the three-way construction tolerance adjustments and connection of the mullion to the anchoring system.
U.S. Pat. No. 9,683,367 and U.S. Patent Application Publication No. 2017/0241133 disclose a mullion connection system having three components—an anchoring device, a mullion connection bridge, and a mullion connection clip. The anchoring device is anchored to the building structure (e.g., secured to a concrete floor slab), the mullion connection bridge is secured to the anchoring device and the mullion connection clip, and the mullion connection clip is secured to the mullion.
In that system, up-and-down construction tolerance adjustments are automatically done by using a mullion connection clip that is slidably engaged with the mullion using matching male and female joints. Because the mullion connection clip can slide along the length of the mullion in the up-and-down direction, the mullion connection clip will be placed at the proper up-and-down position by simply engaging the mullion connection clip with the mullion and sliding the mullion connection clip down to the anchoring device on the floor slab. In-and-out adjustments are made using a marked stick to control the theoretical distance between the back flange of the mullion and the reference line marked on the floor and making adjustments by relative in-and-out positioning of the mullion connection clip and mullion connection bridge. The mullion is secured in the final in-and-out position by tightening bolts between the mullion connection clip and the mullion connection bridge. Left-to-right adjustments are made by moving the mullion laterally to line up the center of the mullion with the mullion center mark on the floor slab and relative left-to-right positioning of the mullion connection bridge and anchoring device. The mullion is secured in the final left-and-right position using a fastener securing the mullion connection bridge to a load resisting lip of the anchoring device. The second and the third adjustments can be done simultaneously, however, it is a time consuming process since it must be done for each individual mullion.
It is desirable to have a mullion anchoring system that can be installed on a cured concrete floor slab at the proper in-and-out and left-and-right positions to allow the mullion to be engaged with the anchoring device without the need for construction tolerance adjustments and without the need for a fastener between the mullion and mullion anchoring device. This would accomplish automatic three-way construction tolerance adjustments in erecting mullions, resulting in significant reduction in field labor costs.